The use of hand-held electronic devices capable of simultaneously playing video and audio are proliferating. Examples of such devices include portable video gaming systems, portable DVD players, and cell phones. One commonality between hand-held electronic devices is the fact that they primarily run on batteries, therefore, conservation of energy is extremely important.
One important component of hand-held electronic devices is the output of sound. Digitally recorded sound must typically be input to and processed by a sound processor included within the electronic device. The sound is typically input as a series of frames, one for each voice in the system (e.g., 64), and each frame comprises some number of sound samples (e.g., 32). The sound processor typically processes each of the voices serially, although parallel processing is also done. In serial embodiments, the sound processor has a finite amount of time in which to process each voice. The sound processor uses each voice time slot to control how the voices in the input sound will be modified by certain operations in the during the data processing stage. Example of operation are effects that the sound processor may apply to the voices. Such effects commonly include gain envelopes, low frequency oscillator (or “LFO”) incorporation (as gain or pitch), and pitch envelopes. Typically, the sound processor is connected to a host processor in the electronic device that executes a software program responsible for producing the video and/or sound, and it is the software program that instructs the sound processor effects to apply to the voices.
Due to the amount of possible operations that can be performed on each voice, the sound processor is one component in a hand-held electronic besides the video system that drains power. Conventional methods for reducing power consumption of components of handheld devices that require low power are to employ general techniques such as clock gating and operand isolation to the integrated circuits comprising the components. However, these techniques are implemented during the design of the device and permanently limit the capabilities of the components.
Accordingly, what is needed is an improved architectural power saving feature that reduces power consumption of a sound processor, but does not permanently limit the operations capable of being performed by the sound processor. The present invention addresses such a need.